The aim of this research is to develop a reliable and valid scale to determine the mathematical thinking skills of gifted students. In addition, with the developed scale, thinking skills of gifted students was examined in terms of various variables. In this context, the research was carried out on two different study groups. The first stage of this research was the development of the scale, and the data obtained from 410 gifted students. The second stage of this research was the testing process of the developed scale, and it was carried out on the data obtained from 393 gifted students. While developing the scale, confirmatory factor analysis, exploratory factor analysis, Guttman Split-half values reliability, Cronbach Alpha internal consistency coefficient calculations were performed. As a result of analyses, the total variance percentage of the scale consisting of 16 items and four factors was obtained as 60.781%. It was concluded that the model obtained from confirmatory factor analysis applied was at an acceptable level. For the whole scale, Cronbach's alpha value of the scale was determined as 0.841. As a result of this study, a reliable and valid scale was developed to determine mathematical thinking skills of students. In addition, through the scale developed, it was concluded that thinking skills of the students showed differences according to gender, group, grade level and education status.